System and method for internally backwashing a filter of a robotic swimming pool cleaner

ABSTRACT

A self-propelled robotic cleaning apparatus for cleaning a submerged surface of a pool or tank includes a housing defining an interior chamber containing a filter assembly for filtering water flowing through at least one water inlet formed in the base plate. A filter backwash assembly is positioned within the interior chamber and has at least one fluid discharge outlet for providing a pressurized flow of a fluid towards the exterior surface of the filter assembly as a backwash to rinse and dislodge the debris therefrom.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a divisional of U.S. patent application Ser.No. 13/545,339, filed Jul. 10, 2012, the content of which isincorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The present invention relates to a submersible robotic pool and tankcleaning apparatus having one or more internal filtering devices forseparating and isolating undesirable contaminants and debris from thepool or tank environment, and more specifically to a filter backwashsystem for improving the maintenance and operation of the one or moreinternal filtering devices within the cleaning apparatus.

BACKGROUND OF THE INVENTION

Robotic pool cleaning devices are mounted on rotatable supports, such aswheels, brushes and/or tracks, and are propelled or otherwise travelalong submerged surfaces of a pool, tank or the like and, through theuse of suction, thereby “vacuum” the pool surfaces over which they pass.The pool cleaning devices can be propelled over the surfaces of the poolby a directional or random water jet propulsion system, or by one ormore drive motors that are coupled to (e.g., to the wheel axles) andcause the rotation of the rotatable supports.

The cleaning devices configured with an internal filtering system havean interior chamber with one or more filters mounted therein. Theinternal filtering systems are effective to capture and isolatecontaminants and/or debris from portions of the interior chamber whereit is highly desirable that contamination not encroach. The filteredwater is then discharged back into the pool or tank as a pressurizedstream.

The filter can be fabricated from a mesh material that is sewn into aconfiguration that is stretched over and/or held in place over asupporting open framework that is securely positioned inside thecleaning body or housing. Alternatively, rigid filter cartridges can beused in which the filter medium is a pleated web and which can alsoinclude an open mesh wire or plastic support to reduce collapsing of thefiner pleated filter material. Filter cartridges are commonlycylindrical and include a separate flexible seal in the form of a ringthat is fitted over the circular openings at each end.

During cleaning operations, the debris captured by the filter medium caneventually cover and block the porous filter medium thereby reducing thefiltering efficiency of the filter, and hence diminish the cleaningoperation of the cleaner. Presently, pool cleaners having one or moreinternal filters must be cleaned manually to remove and unclog thedebris that is captured by the filter. The filters can be in the form ofany well-known filter bag, screen, filter cartridge or filter canister.

When the filter becomes filled or its surface area is clogged withdebris, the end user must remove the cleaner from the pool, open thecleaner to gain access to its interior, and disengage any fasteners thatretain the filter in its required position within the interior therein.The filter is then removed from the cleaner and the debris is removedfilter therefrom by hand and/or by running clean water over the filter,illustratively under a faucet or a conventional garden hose. Once thefilter is rinsed and cleaned from debris, the end user manuallyreinstalls the filter back into the interior chamber by properlypositioning and securing it therein, and then closing the cleanerhousing. The pool cleaner can then be submerged back in the pool forfurther pool cleaning operations.

The maintenance involved to clean the one or more filters is notgenerally complicated, but it can be time consuming and require the enduser to get his hands “dirty” to fulfill the required maintenance taskof cleaning the filter. In addition, the end user must carefullyreinstall the filter to its correct position and/or alignment within theinterior chamber and properly secure it therein, since an improperlyinstalled filter can cause physical damage the filter and/or allowundesirable debris to pass therethrough without being captured.

SUMMARY OF THE INVENTION

The above problems and disadvantages are solved and avoided by theembodiments of the apparatus and methods of the present invention thatare described below. In the description that follows, it will beunderstood that the cleaner moves on supporting wheels, brushes, rollersor tracks that are aligned with the longitudinal axis of the cleanerbody when it moves in a straight line. References to the front orforward end of the cleaner will be relative to its then-direction ofmovement.

The present invention is directed to various embodiments of filtercleaning assemblies and systems installed within the interior chamber ofthe automated pool or tank cleaner. As described in greater detailbelow, a filter cleaning assembly can be provided by various structuresthat dispense pressurized streams of water along at least portions ofthe exterior surface of the filter medium of a filter device in order tobackwash or otherwise rinse the porous surface of the filter medium tofree and disperse any debris that may be ensnared thereon and/orotherwise impairs or occludes the flow of water through the filtermedium. The filter cleaning assemblies described herein include an inletformed in the housing of the cleaner that is configured to receive apressurized source of clean water, preferably through a fitting attachedto a conventional garden hose, and the pressurized water from the inletflows through the filter cleaning assembly from which it is streamed orsprayed over the outer surface of the filter medium. In this manner, theforce of the water pushes any debris that is trapped against the surfaceof the filter medium away therefrom and downwards to the bottom of theinterior chamber where the debris can be discharged through one or moreaccess panels or the inlet port(s) formed on the bottom or base plate ofthe cleaner. Preferably, the base plate below the filter assembly isremoved and the debris backwashed from the filter can drop directly intoa suitable receptacle or surface for disposal.

In general, a self-propelled robotic cleaning apparatus for cleaning asubmerged surface of a pool or tank can include a housing having a frontportion, an opposing rear portion and adjoining side portions definingthe periphery of the apparatus. A base plate with at least one waterinlet is mounted to the lower portion of the housing.Rotationally-mounted supports are coupled to the housing to move thecleaning apparatus along a cleaning path. In an embodiment, a water pumpis mounted within the interior chamber of the housing. The water pump isconfigured to draw water and debris from the pool or tank through theone or more water inlets formed in the base of the cleaner forfiltering, and then causes the discharge of the filtered water throughat least one water discharge outlet. The internal water pump provides apressurized water jet that is expelled from the water-discharge outletand which can be configured to propel the cleaner in a forward orreverse direction. Alternatively, the water pump can be providedremotely from the cleaner and connected by a hose. In this latterembodiment, one or more drive motors are provided to rotate therotationally-mounted supports to move the cleaner in a forward andrearward directional path.

In one embodiment, a self-propelled robotic cleaning apparatus forcleaning a submerged surface of a pool or tank includes a housing havinga cover and a base. The base has at least one water inlet, and thehousing cover is removably fastened to the base to define an interiorchamber. A means for propelling the cleaning apparatus includingrotationally-mounted supports is coupled to the housing for moving theapparatus in a forward direction over the submerged surface of the poolor tank. A filter assembly is positioned within the interior chamber forfiltering water by capturing debris flowing through the at least onewater inlet from the pool or tank. A filter backwash assembly ispositioned within the interior chamber and has at least one waterdischarge outlet for providing a pressurized flow of a fluid (e.g.,water or a gas) towards the filter assembly to rinse and dislodge thedebris therefrom.

In one aspect, the filter backwash assembly includes a plurality oftubes suspended from the housing cover and is configured to circumscribeat least a portion of the filter assembly. The at least one fluiddischarge outlet includes a plurality of spaced-apart perforations. Inanother aspect, the filter backwash assembly is suspended from amounting bracket having a lower portion coupled to the plurality oftubes, and an upper portion extending through an orifice formed in thehousing cover. The upper portion can be configured to receive apressurized fluid from an external source. In one aspect, the upperportion of the mounting bracket is configured to receive the fluid froma hose.

In another embodiment, the filter backwash assembly includes anoscillating sprinkler suspended from the housing cover and is configuredto oscillate in a predetermined pattern over the filter assembly. In oneaspect, the at least one fluid discharge outlet includes a plurality ofspaced-apart perforations that are directed toward the filter assembly.In another aspect, the oscillating sprinkler extends normally from thehousing cover relative to a longitudinal axis of the cleaning apparatus.

In yet another aspect, the at least one fluid discharge outlet is asprinkler arm, and the oscillating sprinkler further comprises a meansfor oscillating the sprinkler arm coupled to the sprinkler arm. In oneaspect, the oscillating means includes a fluid turbine operativelycoupled to the sprinkler arm. Alternatively, the oscillating meansincludes a motor coupled to the sprinkler arm.

In yet another embodiment, the filter backwash assembly includes arotating sprinkler assembly suspended from the housing cover andconfigured to rotate over the filter assembly. In one aspect, the atleast one fluid discharge outlet includes a plurality of spaced-apartperforations that are directed toward the filter assembly. In anotheraspect, the rotating sprinkler assembly includes a plurality ofsprinkler arms extending radially outward at equally spaced-apartintervals.

In an embodiment, the filter backwash assembly includes a tubularsprinkler assembly suspended from the housing cover and configured torotate above the filter assembly. In one aspect, the tubular sprinklerassembly includes a fluid turbine for rotating the tubular sprinklerassembly.

In yet another embodiment, the cleaning apparatus further comprisesmeans for releasing the fluid and debris from within the interiorchamber of the cleaning apparatus. In one aspect, the means forreleasing the fluid and debris includes a tray slidably coupled to atleast one of the base and/or housing. In another aspect, the trayincludes a debris outlet port.

In one aspect, the means for releasing the fluid and debris includes anaccess panel formed in a sidewall of the housing. In still anotheraspect, the means for releasing the fluid and debris includes a debrisoutlet port formed in the base.

In yet another embodiment, a method for cleaning a filter mounted in aninterior chamber of a self-propelled robotic cleaning apparatus thatcleans a submerged surface of a pool or tank is provided. The methodcomprises coupling an external source of fluid to an adapter which isprovided on a housing of the cleaning apparatus. The adapter is coupledto an internal sprinkler assembly mounted within the interior chamber. Aflow of the fluid is provided from the external fluid source to theinternal sprinkler assembly mounted within the interior chamber for apredetermined time. The fluid from the internal sprinkler assembly isdistributed over at least a portion of the filter mounted in theinterior chamber. In one aspect, the fluid and debris is discharged fromthe interior chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in further detail below and withreference to the attached drawings in which:

FIG. 1 is a top, right side perspective view of an embodiment of aself-propelled robotic pool or tank cleaner suitable for receiving afilter backwash assembly of the present invention;

FIG. 2 is an exploded perspective view of the pool cleaner of FIG. 1illustrating a first embodiment of the filter backwash assemblypositioned over the filter assembly within an interior chamber of thecleaner of FIG. 1;

FIG. 3 is a cross-sectional side elevation view of the pool cleanertaken along lines 3-3 of FIG. 1 illustrating the relationship of thebackwash assembly of FIG. 2 within the interior chamber of the poolcleaner;

FIG. 4 is a cross-sectional front elevation view of the pool cleanertaken along lines 4-4 of FIG. 1 illustrating the filter backwashassembly of FIG. 2;

FIG. 5 is the same as FIG. 4 schematically illustrating the pattern of afluid sprayed on the filter medium of the filter assembly of the poolcleaner;

FIG. 6 is a cross-sectional front elevation view of the pool cleanertaken along lines 4-4 of FIG. 1 illustrating a second embodiment of thefilter backwash assembly while spraying water over the filter assemblyof the pool cleaner;

FIG. 7 is a cross-sectional front elevation view of the pool cleanertaken along lines 4-4 of FIG. 1 illustrating a third embodiment of thefilter backwash assembly while spraying water over the filter assemblyof the pool cleaner;

FIG. 8 is a cross-sectional front elevation view of the pool cleanertaken along lines 4-4 of FIG. 1 illustrating a fourth embodiment of thefilter backwash assembly while spraying water over the filter assemblyof the pool cleaner.

FIG. 8A is a cross-sectional side elevation view of the fourthembodiment of the filter backwash assembly taken along lines 8A-8A ofFIG. 8;

FIG. 8B is a cross-sectional front elevation view of a water turbinetaken along lines 8B-8B of FIG. 8A and suitable for use in the fourthembodiment of the filter backwash assembly;

FIG. 9 is a top, right side perspective view of an embodiment of theself-propelled robotic pool or tank cleaner of FIG. 1 illustrating aslidable tray extending from the bottom of the cleaner for removingdebris during maintenance;

FIG. 10 is a side elevation view in partial cross-section of theslidable tray taken along lines 10-10 of FIG. 9;

FIG. 11 is a front elevation view in partial cross-section of theslidable tray taken along lines 11-11 of FIG. 10 and illustrating aretractable debris outlet port in an closed state; and

FIG. 12 is an exploded cross-sectional view of the slidable tray of theretractable outlet port in an open state for removing the debris duringmaintenance of the pool cleaner.

To facilitate an understanding of the invention, identical referencenumerals have been used, when appropriate, to designate the same orsimilar elements that are common to the figures. Further, unless statedotherwise, the features shown in the figures are not drawn to scale, butare shown for illustrative purposes only.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

For purposes of providing a better understanding the invention asfurther described below, terms connoting direction and positioning ofcomponents are defined as follows:

longitudinal axis of the cleaner is defined as extending centrallythrough the cleaner in the direction of movement;

movement of the cleaner in a forward direction is the direction that thecleaner is presently being propelled or driven along its cleaning path;

movement of the cleaner in a reverse direction is a direction that isopposite to the forward direction along the cleaning path;

the front of the cleaner is defined as the portion of the cleanerextending perpendicular along the longitudinal axis in the forwarddirection of movement as the cleaner travels along its cleaning path;

“top”, “bottom”, “upper” and “lower” are adjectives that denotedifferent cleaner components, as well as define the relative positioningof such components with respect to a central vertical axis extendingcentrally through the housing cover and base of the cleaner;

the backwash assembly of the present invention utilizes a “fluid” forpurposes of cleaning the interior chamber and/or filter medium and suchfluid can be in the form of a liquid (e.g., water) or a gas (e.g.,compressed air); and

for convenience, the apparatus may be referred to as a “pool cleaner” orsimply a “cleaner”.

Referring generally to FIGS. 1-5, an embodiment of a self-propelledrobotic pool or tank cleaner 10 illustrating an internal filter backwashassembly 80 (see FIG. 2) of the present invention is illustrativelyshown. The pool cleaner 10 generally comprises a housing 11 having acover 12 and a base plate, or base 14 with at least one water inlet 16(see FIG. 3) formed in the bottom surface 27 of the base 14. The housingcover 12 is removably fastened over the base 14 to define an interiorchamber 26. The housing cover 12 and base 14 are removably fastened withone or more fasteners (not shown), such as a clasp, latch, spring clip,bolt or other well-known fasteners. A gasket or other seal (not shown)can be inserted between the base 14 and cover 12 to prevent waterflowing therebetween into and out of the interior chamber 26. Thehousing cover 12 and base 14 are preferably made of a polymeric materialthat is resistant to the sun and pool chemicals, such aspolyvinylchloride (PVC) or polypropylene, among other well-knownthermoplastic materials, aluminum and/or alloys thereof, and/orcombinations thereof, and/or other water impermeable materials.

Rotationally-mounted supports 18 are coupled to the housing 11 formoving the cleaner 10 over the submerged surface of the pool or tank 2.As shown in the drawings, the rotationally-mounted supports 18 arewheels mounted on axles 20, in which a pair of wheels 18 are rotatablymounted to opposing ends of a single axle at one end of the housing. Asingle wheel is centrally mounted to the other end of the housing toenable steering of the cleaner 10. For example, steering motor 24 can beused to change the direction of the wheel 18 to turn the cleaner inaccordance with a random or predetermined cleaning pattern.Alternatively, a pair of wheels can be mounted on the opposing ends ofaxles positioned at opposite ends of the cleaner 10. A person ofordinary skill in the art will appreciate that the rotationally-mountedsupports 18 can be or include one or more tracks. For a detailedunderstanding of various wheel/axle arrangements and steering controlmechanisms, the reader is directed to commonly-assigned U.S. Pat. No.6,742,613, the contents of which are incorporated herein by reference inits entirety.

The cleaner 10 also includes one or more brushes 40 that are mounted atopposing ends of the housing. The brushes 10 can be separate from therotationally mounted supports 18 as illustratively shown in thedrawings. Alternatively, the brushes can be formed as a part of therotationally mounted supports 18 such as rollers and extend transverseto the front and/or rear ends of the cleaner. As illustratively shown inFIG. 1, the brushes can pivotally rotate upward and downward to permitaccess into the interior chamber 26 of the cleaner during maintenance.For example, brush 40 proximate the pair of support wheels 18 can pivotupward and downward, as illustratively shown in phantom in FIG. 1. For adetailed understanding of various brushes that can be implemented andtheir arrangements on the cleaner, the reader is directed to theabove-identified commonly-assigned U.S. Pat. No. 6,742,613.

The cleaner 10 can be propelled by one or more drive motors (not shown)which engage and rotate one or more of the wheels 18 in a well-knownmanner. In this embodiment, control means (not shown) are provided toperiodically reverse the direction of movement to assure that thecleaner does not become immobilized, e.g., by an obstacle in the pool.If, for example, the pool cleaner does not change its orientation withrespect to the bottom or sidewall as indicated by a signal from anon-board sensor (e.g., mercury switch) indicating that such transitionhas occurred during the prescribed period, e.g., two minutes, a controlcircuit will automatically change the direction of the drive means(i.e., drive motors or water jet propulsion valve assembly) in order topermit the cleaner to move away from the obstacle and resume itsscanning pattern. Sensors, such as magnetic and infrared-responsivesignaling devices can also be provided to change the direction ofmovement in response to prescribed conditions, e.g., absence of forwardmovement due to an obstacle. In addition, the control means canautomatically steer the cleaner to the right or left while moving ineither the forward or reverse direction. Power for the cleaner 10 can besupplied by a buoyant electrical cable 22 (shown in phantom in FIG. 3)attached to an external power source, such as a transformer or a remotebattery contained in a floating housing at the surface of the pool 2,although such power sources are not considered limiting. Alternatively,one or more rechargeable battery packs (not shown) can be providedinternally to provide power to the cleaner 10.

Referring to FIGS. 3 and 4, the cleaner 10 further includes at least onewater inlet 16 formed through the bottom surface 27 of the base 14, afilter assembly 50 positioned within the interior chamber 26, and awater discharge assembly 30 for discharging water from the interiorchamber 26 of the cleaner 10. The water discharge assembly 30 includesat least a water pump 60 and a discharge port 32. In the embodimentshown in the drawings, the water pump is also provided within theinterior chamber 26. Alternatively, in a second embodiment, the waterpump 60 is remotely located from the cleaner 10. In either embodiment,the water pump 60 creates a low presser environment within the interiorchamber 26, which causes water and debris from the pool or tank 2 to bedrawn through the at least one water inlet 16 into the interior chamber26. The drawn pool water and debris is filtered by the filter assembly,and the filtered water is discharged from the cleaner by the waterdischarge assembly 30. The debris and/or other contaminants areseparated from the intake water and isolated within the interior chamber26 by the filter assembly 50, as described below in further detail withrespect to FIGS. 2-8.

Referring now to FIG. 3, the water discharge assembly 30 includes a pairof water pumps, one of which is mounted within the interior chamber 26proximate the forward direction end of the cleaner 10 and the other ismounted within the interior chamber 26 proximate the rearward directionend of the cleaner 10. Each water pump 60 includes a motor 62 thatrotates an impeller or propeller 64 via a rotatable shaft 66. The waterpumps 60 are provided with electrical power via the buoyant power cable22 or internal batteries, and are individually controlled by acontroller 68.

A discharge port 32 is formed on opposing forward and rearward directionends of the housing 11 or housing cover 12 and can include a dischargeport cover or flap 34, which can be spring loaded and opened and closedby the pressurized water jet that is expelled through the discharge port32 by the corresponding water pump 60. During operation, one of the dualwater pumps 60 is powered on, while the other water pump is off. Asshown in FIG. 3, the left side water pump 60 is powered on while theright side water pump is turned off. The low pressure environment withinthe chamber created by the powered on water pump 60 draws the waterthrough the one or more inlets 16, and through the filter assembly 50.The high water pressure from the powered on pump 60 is directed andforced out of the interior chamber 26 through the correspondingdischarge port 32 as a water jet as illustratively shown by the arrowson the right side of the drawing. The force of the water jet issufficient to push and maintain the discharge port flap 34 in an openposition. The water jet expelled by the cleaner propels the cleanerforward (e.g., to the right of the drawing) until the cleaner contactsor otherwise senses an opposing wall or obstacle. At that time thepowered-on pump is switched off by the controller 68 and the powered-offpump 60 is subsequently powered on to reverse the direction of movementof the cleaner in a similar manner.

Although the dual pumps 60 are shown as separate pumps installed onopposite sides on the interior chamber 26, other arrangements of thedual water pump propulsion system can be provided. For example, a waterpump having dual propellers positioned along a longitudinal axis in theinterior chamber with one or more directional discharge conduits topropel the cleaner in a forward direction can be implemented, asillustratively shown and described in commonly assigned U.S. patentapplication Ser. No. 13/135,684, filed Jul. 12, 2011 and PCT applicationno. PCT/US2011/047435, filed Aug. 11, 2011, both entitled “Water JetPool Cleaner with Opposing Dual Propellers”, and both of which areincorporated by reference herein in their entireties.

In yet another embodiment, the pool cleaner can include a vertical waterpump mounted in the interior chamber and a flap valve assembly providedover the water pump to selectively discharge the water jet to propel thecleaner in the forward direction. For a detailed understanding of avertically mounted pump and flap valve assembly, the reader is directedto commonly assigned U.S. Pat. Nos. 6,412,133 and 7,900,308, thecontents of which are incorporated by reference in its entirety.

In any of the water pump embodiments described above, the waterdischarge assembly 30 includes a directional water jet valve propulsionassembly which controls the direction of a pressurized water jet streamto propel the cleaner 10 in a forward direction, where the front of thecleaner 10 is defined as the direction in which the cleaner 10 is thenmoving. Accordingly, drive motors for rotating the wheels 18 are notrequired to move the cleaner 10 along the submerged surface of the poolor tank 2.

In still another embodiment, a single pump can be provided eitherinternally or externally to create the low pressure environment to drawthe pool water and debris into the interior chamber for filtering andsubsequent discharge of the filtered water from the cleaner. However,propulsion of the cleaner is provided by one or more drive motors thatcause the rotational supports (e.g., wheels or tracks) to rotate andmove the cleaner along its cleaning path.

Referring now to FIGS. 2-5, a filter assembly 50 is positioned withinthe interior chamber 26 formed below the underside 25 of the housingcover 12 and is secured to the bottom interior surface 27 of the base14. The filter assembly 50 includes a filter body 52 having an upperportion in fluid communication with side walls 53 that terminate at thebottom interior surface 27 of the base 14. The filter body 52circumscribes the at least one inlet 16 and is preferably rectangular inshape, although other filter body shapes are contemplated, such ascircular, oval, and/or other combinations of shapes. The filter body 52can be a screen or mesh fabricated from a tear-resistant andcorrosion-resistant polymeric non-corrosive material, such as stainlesssteel or other sturdy material which can retain its shape with minimaldeformation. Alternatively, the filter body 52 can be a filter bagfabricated from nylon or other appropriate filter media well known tothe art. The filter body 52 can also be pleated or corrugated toincrease its surface area. In another aspect, the filter body can alsobe formed with a supporting skeleton or frame structure to prevent thecollapse and/or deformation of the filter medium as the pressure dropincreases.

Water from the pool or tank that is drawn through the water inlets 16flows into the portion of the interior chamber 52 that is circumscribedby the interior surface of the filter body 52 and the bottom surface ofthe base 14. The area within the circumference of filter body defines an“unfiltered zone”. As the water flows through the filter body 52 intothe exterior area of the filter that defines a “filtered zone”,undesirable debris or particles are isolated and retained in theunfiltered zone, and the filtered water is subsequently discharged bythe water discharge assembly 30 into the pool or tank 2.

As debris is collected and retained by the filter body 52, periodicmaintenance is required to clean the filter. The present invention isdirected to an internal backwash assembly 80 to assist the user inrinsing off and eliminating the collected debris from the interiorchamber 26 of the cleaner 10.

Referring again to FIGS. 2-5, a first embodiment of the internalbackwash assembly 80 is illustratively shown. The backwash assembly 80is mounted within the interior chamber 26 and is positionedsubstantially adjacent the external surface of the filter body 52. Thebackwash assembly 80 includes a water inlet conduit adapter 82 and aplurality of tubes 90 each having a plurality of perforations 92 forspraying water within the interior chamber 26 during maintenance of thecleaner 10. Although the present invention is illustratively describedas dispersing or spraying water within the interior chamber 26 and overthe filter body 52, a person of ordinary skill in the art willappreciate that other fluids can be utilized, including a pressurizedflow of gas (e.g., compressed gas) from a compressor (not shown) orother source of pressurized fluid suitable for backwashing the interiorchamber and/or filter 50 during maintenance of the cleaner 10.

More specifically, the inlet conduit adapter 82 is preferably acylindrical tube extending vertically through an orifice 83, which isformed in the housing 12 and sized to receive the cylindrical inletconduit adapter 82. The cylindrical inlet conduit adapter 82 isillustratively shown extending vertically through the housing cover 12.However the positioning of the inlet conduit adapter is not consideredlimiting as the inlet conduit adapter 82 can alternatively be positionedin a sidewall of the housing 11 or housing cover 12. The inlet conduitadapter 82 is preferably fabricated from plastic or acorrosion-resistant metal material and includes an external portion 84that is configured and dimensioned to connect to or otherwise receive anexternal source of water, such as delivered through a conventionalgarden hose 91. The external portion 84 of the inlet conduit adapter 82is positioned over the external surface of the housing 11 or housingcover 12. A cap or seal 88 is provided to cover the external portion 84when the backwash assembly 80 is not in use. The adapter 82 furtherincludes an internal portion 86 which extends from the external portion84 through the orifice 83 and into the interior chamber 26.

The internal portion 86 of the adapter 82 includes one or more outletfittings 85, each of which is dimensioned to connect to an end of aperforated tube 90. The one or more perforated tubes are arranged tocircumscribe at least a portion of the filter assembly 50 to providepressurized streams or a spray of water directed at the filter assembly50 during maintenance of the cleaner 10. The plurality of perforations92 can be formed in the wall of the tube at predetermined locations tocontrol the direction and volume or pressure of the water spray which ispredominantly at the filter medium of assembly 50. Alternatively, theplurality of perforations 92 can be formed around the circumference ofthe tubes 90 so that the water spay is directed at the filter assembly50 and in other directions such as towards the inner walls of theinterior chamber 26, as illustratively shown in FIG. 5.

Referring again to FIGS. 2-5, the arrangement of the tubes 90 ispreferably configured to circumscribe and/or conform to the shape of thefilter assembly 50 so as to spray at least the top portion of the filterbody 52 to thereby push debris therein downwards to the bottom surface27 of the base 14. A plurality of tube fittings or connectors 87 can beutilized to connect adjacent ends of two or more tubes 90 together,based on the configuration of the backwash assembly 80. The tubes 90 canbe linear and/or arcuate and are preferably connected end-to-end (in anydirection) such that a closed circulatory system is formed. In thismanner, the water flowing through the one or more tubes 90 is dispensedonly through the plurality of perforations 92. In an alternativeembodiment, one or more tubes 90 can remain open at one end to provide alarger volume of a pressurized stream of water that is directed at aparticular area of the filter body 52.

The backwash assembly 80 can also include one or more support members 89that extend from the internal portion 86 of the inlet conduit adapter 82to one or more of the tube fittings 87 or otherwise retain the tubesusing known fasteners or systems to provide additional support for thebackwash assembly 80 within the interior chamber 26. The support members89 can be rails or beams fabricated from plastic, ceramic or anon-corrosive metal material. The support members 89 extend over thefilter 50 a distance that is suitable to disperse the fluid with enoughpressure and force to rinse or otherwise dislodge the debris withoutdamaging the filter medium.

Referring now to FIG. 6, a second embodiment of the internal backwashassembly 80 is illustratively shown. In a manner similar to the firstembodiment, the backwash assembly 80 is mounted within the interiorchamber 26 and is positioned substantially adjacent the external surfaceof the filter body 52. The second embodiment of the backwash assembly 80includes a water inlet conduit adapter 82 and a sprinkler assembly 100,which includes a sprinkler arm 102, oscillating means 110, an interiorconnecting tube 106 and one or more support arms 108. The sprinkler arm102 includes a plurality of perforations 104 for spraying water withinthe interior chamber 26 during maintenance of the cleaner 10.

The backwash sprinkler assembly 100 is illustratively shown mounted atopposing ends to the upper interior surface of the housing cover 12 bythe support arms 108. The support arms 108 can be formed as part of thehousing cover 12 by injection molding such that the opposing ends of thesprinkler arm 102 are retained or clasped by snap-fitting to the supportarms. Alternatively, the support arms can be secured to the upperinterior surface of the housing cover 12 and/or the opposing ends of thesprinkler arm 102 by one or more fasteners. The sprinkler assembly 100is illustratively shown as being mounted in the interior chamber in adirection normal to the longitudinal axis of the cleaner 10. However, aperson of ordinary skill in the art will appreciate that the sprinklerassembly 100 can be mounted within the interior chamber 12 in otherdirections, such as along the longitudinal direction, among otherdirections.

The sprinkler assembly 100 includes a water inlet port 112 positioned atthe proximal end of the sprinkler arm 102. A flexible interior tube orhose 106 is secured at one end to the inlet port 112 and to an outletfitting provided at the internal portion 86 of the inlet conduit adapter82. The external portion 84 of the inlet conduit adapter 82 ispreferably the same as described with regard to the embodiment shown inFIGS. 3-5 and extends through an orifice 83 formed in the housing cover12 or housing sidewalls 11. The external portion 84 is also configuredto receive or connect to a conventional garden hose 91 as describedabove. A conventional shut-off valve 93 (see FIG. 6) of any known designcan be connected (e.g., threaded and/or quick connector) between thedownstream end of the garden hose 91 and the external portion 84 of theinlet conduit adapter 82 to enable the user to control the external flowof water into the sprinkler assembly 100 while standing next to thecleaner 10 instead of having to walk over to the upstream end of thegarden hose which is connected to a water tap or spigot, or bringing thecleaner near the water tap to backwash (i.e., rinse) the interiorchamber 26 and filter body 52. The shut-off valve 93 can be utilized forany of the embodiments described herein.

An oscillating means (or oscillator) 110 is provided at one end of thesprinkler arm 102. In one embodiment, the oscillating means 110 is anelectric motor that is configured to rotate the sprinkler arm 102 at apredetermined number of degrees of rotation about the longitudinal axisof the sprinkler arm 102. In this embodiment, the oscillator 110, i.e.,electric motor, can be mounted at either end of the sprinkler arm 102and is electrically connected to the controller 68 via electricalconductors (not shown) for providing power to and controllingoscillation of the sprinkler arm 102.

Preferably the oscillation means 110 includes a water turbine, which isrotated by the force of the water flowing from the external source,e.g., through the garden hose 91. An illustrative water turbine isdescribed below with reference to FIG. 8B. The oscillation means 110 issimilar to that of a well-known oscillating lawn sprinkler where thewater turbine is centrally aligned and coupled to a cam. A rod or arm isprovided with one end that extends from the cam and an opposing endconnected to an end of the sprinkler arm 102. The incoming water fromthe external source flows to the water turbine to causes it to rotate,and is then channeled to the sprinkler arm 102, which in turn sprays thewater through the perforations 104 to backwash the filter body 52 below.

During operation, water from the garden hose 91 flows through theadapter 82, the interior hose 106 and the inlet port 112, and a portionof the water flow is diverted to rotate the water turbine providedwithin the proximal end of the sprinkler arm 102. The force of thediverted water rotates the turbine which in turn rotates the cam. Therotating cam moves the support arm back and forth so that the sprinklerarm also rotates positively and negatively (i.e., back and forth) apredetermined number of degrees from its normal centered position. Forexample, the sprinkler arm can rotate one-hundred and eighty degrees(180°), i.e., ninety degrees positively and negatively with respect to acentral axis extending perpendicularly upward from the base 14. The rateof rotation of the cam can be controlled by a gear reduction system(e.g., gear train), which reduces the transferred rate of rotation ofthe water turbine from a few hundred rotations per minute (rpm) to alesser suitable rate of rotation per minute for efficiently cleaning thefilter body 52.

Referring to FIG. 7, a third embodiment of the backwash assembly 80 isillustratively shown. In this embodiment, the backwash assembly 80comprises the adapter 82 and a rotating sprinkler assembly 120, whichincludes a central rotatable hub 122 having one or more sprinkler arms124 extending radially outward therefrom. The sprinkler arms 124 includeperforations 126 configured and positioned to spray water onto thefilter media of body 52. The rotating sprinkler assembly 120 is mountedor otherwise coupled to the internal portion 86 of the adapter 82 and ispositioned above the filter body 52.

During maintenance, the water from the external source (e.g., gardenhose 91) is provided to the sprinkler assembly 12 via the adapter 82 asdescribed above. The rotating sprinkler assembly 120 is rotatablyattached to the internal portion 86 of the adapter preferably withbearings to facilitate smooth rotation thereof. The hub 122 includes afixed water turbine (not shown) with angled blades. Water flowing fromthe external source 91 contacts the turbine and causes the hub 122 andsprinkler arms 124 to contemporaneously rotate about the central axis ofthe sprinkler assembly 120. The water is further channeled through eachof the sprinkler arms 124 and is dispersed or otherwise sprayed from theperforations 126 onto the filter body 52. The water sprayed from thesprinkler assembly 120 forces, or otherwise creates a liquid currentflow to effectuate the removal any debris from the upper portion of thefilter body 52 down to the inner surfaced of the base 14, where thedebris can be easily removed, as described below in further detail.

The rotating sprinkler assembly 120 illustratively shows three sprinklerarms 124 extending radially outward from the hub 122. However, a personof ordinary skill in the art will appreciate that the number ofradiating sprinkler arms 124 is not limiting, as one or more sprinkleralms can be implemented. Preferably, there are at least two sprinklerarms 124 radiating outward from the hub 122 which are evenly spacedapart to balance the sprinkler assembly 120 during rotation. A person ofordinary skill in the art will also appreciate that depending on theshape of the filter body, 52, the sprinkler arms 124 can be configuredsubstantially linear and/or include curved portions to maximize thewater spray therefrom onto the filter body 52 and/or the interior wallsof the chamber 26. In an alternative embodiment, the perforations 126 inthe arms 124 can be aligned, such that the water jets therefrom create acommon directional force to cause rotation of the assembly without awater turbine.

Referring now to FIG. 8, a fourth embodiment of the backwash assembly 80is illustratively shown. The filter body 52 is illustratively shown as asemi-rigid V-shaped mesh or fabric material that has its opposing endsattached (e.g., clipped or otherwise fastened) to the interior surfaceof the housing cover 12. The apex of the V-shaped filter body 52 isillustratively curved and centrally located below the longitudinal axisof the water pump 60, and the debris accumulates below the filter body52. The shape of the filter body 52 is for illustrative purposes onlyand does not form a part of the invention.

The backwash assembly 80 includes a tubular sprinkler assembly 130mounted in the interior chamber 26 of the housing 11 with the waterinlet conduit adapter 82 providing water flow thereto from an externalsource, such as a conventional garden hose 91, as described above withrespect to the other embodiments. The inlet conduit adapter 82 ismounted through an orifice 83 formed in a sidewall of the housing cover12 such that the internal portion 86 of the adapter 82 extends inwardlyalong the longitudinal axis of the cleaner 10 towards the opposingsidewall of the housing cover 12. Alternatively, adapter 82 and/ortubular sprinkler assembly 130 can be mounted transverse to thelongitudinal axis of the cleaner.

Referring also to FIG. 8A, the tubular sprinkler assembly 130 ispreferably an elongated cylindrical tube having a plurality ofperforations 138 spaced about the tube. A proximal end of the tubularsprinkler assembly 130 is rotatably mounted to the internal portion 86of the adapter 82 and a distal end of the tubular sprinkler assembly 130is rotatably mounted to a support member 132. Preferably, the internalportion 86 of the adapter 82 and the support member 132 each include aset of bearings 134 that are arranged coaxially along the outer surfaceof each end of the tubular sprinkler assembly 130 to facilitate therotation of the tubular sprinkler assembly 130 within the interiorchamber 26 as described in detail below.

The proximal end of the tubular sprinkler assembly 130 includes a fixedwater turbine 136 arranged coaxially therein. The periphery of the waterturbine 136 engages the interior portion of the tubular sprinklerassembly 130 such that the frictional forces therebetween prevent theturbine from rotating within the tubular sprinkler assembly 130.Referring to FIG. 8B, the water turbine 136 can be shaped as a ring andinclude a plurality of angled blades 140 that extend inwardly towards acentral opening 142.

During operation, water flows from the external source through thegarden hose 91 and the adapter 82. The incoming water flows against theplurality of blades 140 to cause the water turbine 136 and tubularsprinkler assembly 130 to rotate in a clockwise or counter-clockwisedirection, depending on the positive or negative angling of the blades140. As illustratively shown in FIG. 8A, the angled blades cause thetubular sprinkler assembly 130 to rotate counter-clockwise from theperspective of the incoming water. Once the incoming water turns theblades, the water flows through the central opening 142 and through theinterior portion of the tubular sprinkler assembly 130, where the wateris sprayed out of the plurality of perforations 138 into the interiorchamber 26 and onto the filter body 52.

The above described embodiments of the interior backwash assembly 80spray a stream of water onto the filter body 52 to clean, dislodge andotherwise remove debris from the filter medium. The dislodged debrisfalls or otherwise moves to the interior bottom surface 27 of the base14, where it can be removed from the cleaner 10. In one embodiment, thehousing 11 can be unfastened and lifted off of the base 14 so that thefallen debris resting on the interior bottom surface 27 of the base 14can be removed by hand.

Referring to FIGS. 9-12, in one embodiment, the cleaner 10 includes atray 150 which is slidably mounted within opposing channels 152 (e.g.,FIGS. 9 and 11) illustratively formed on the bottom, side edges of thehousing 11 or opposing edges of the base 14. The tray 150 can beslidably moved from underneath the cleaner 10 to facilitate the removalof the debris in the interior chamber 26. The channels 152 extendlongitudinally substantially along the length of the cleaner 10. Ifrequired, the brush 40 can be manually lifted upwards to access andslide the tray 150 outward from the bottom of the cleaner 10. The tray150 includes one or more inlet ports 16 for enabling the water and thedebris from the pool to be drawn into the interior of the cleaner 10 andfiltered by the filter body 52 as described above. Each inlet port 16can include a flap or cover 154 which is hinged 156 (FIG. 9) on one sideof the water inlet 16. The cover 154 closes its respective inlet port 16when the water pump 60 is switched off.

Referring also to FIGS. 10 and 11, when the water pump 60 is activated,a low pressure environment within the interior chamber 26 is induced,which causes the hinged covers 154 to turn and extend upward from thebase plate 14 towards the interior chamber 26, as illustratively shownin phantom in FIGS. 10 and 11. Water and debris from the pool is thendrawn into the interior chamber 26 for filtering and discharge.

In addition, the tray 150 can include one or more debris outlet ports160 for allowing the water and debris that is sprayed from the sprinklerassemblies to flow out of the interior chamber 26 of the cleaner 10during maintenance. The debris outlet port 160 can be included to allowthe water to escape from the interior chamber 26 without removing thetray 150 during the filter maintenance process. The tray 150 isillustratively shown as being substantially planar. However, a person ofordinary skill in the art will appreciate that the tray 150 can becurvilinear, arcuate or otherwise curved (e.g. concave) to enhance theflow of the waste water and debris towards the debris outlet port 160.Additionally, channels or grooves (not shown) can be formed in thebottom surface, which are directed from the periphery of the traytowards the outlet port 160.

Referring now to FIG. 12, a debris outlet cover assembly 162 is mountedover the outlet port 160. The outlet cover assembly 162 includes aplanar cover 163 configured to close the outlet port 160, and aresilient member or spring 164 which is attached to the cover 163 by afastener 166. In one embodiment, the resilient member 164 can be shapedas an elongated flat spring having opposing ends fixedly attached torespective opposing ends of the outlet port 160 and a center portionfixedly attached to the planar cover 163 by the fastener 166. The shapeof the debris outlet port 160, its corresponding cover 162 and themanner in which the resilient member 166 is attached therebetween is notconsidered limiting. Additionally, one or more latches 168 (e.g.,rotatable latches) can also be fastened to the underside of the baseplate 14 or tray 150 with a corresponding fastener 169 to lock andretain the cover 163 in a closed position. In this manner, debris isprevented from escaping from the interior chamber 26 when the cleaner 10is being removed from the pool, for example during maintenance.

During the filter cleaning maintenance operation, the water that issprayed from the sprinkler assembly flows onto the filter body 52 andinternal walls of the interior chamber 26. The sprayed water anddislodged debris flow downward to the tray 150 such that the force ofthe water will push the resilient member 164 and cover 162 downward sothat the cover 163 is displaced from and below the outlet port 160. Thesprayed water and small amounts of debris can then flow through theoutlet port 160 and out of the interior chamber 26 so that the interiorchamber does not fill up with the cleansing water. Once the water fromthe external source is turned off, the tray 150 can be slidably removedfrom the bottom portion of the cleaner 10. The user can then access andclean the debris from the filter body 52 and interior chamber 26.

Referring again to FIGS. 4 and 5, an alternative embodiment of theoutlet port 160 is illustratively shown. The outlet port 160 includes adebris outlet cover assembly 162 which has a central portion 165extending upwards into the interior chamber 126 and sized to house acoil-shaped spring 164 with a fastener 166. A flange forming a cover 163is formed at a lower end of the central portion 165. The fastener 166extends normally with respect to the base 14, i.e., through the centralportion 165 of the cover assembly 162 and along the central axis of thecoil spring 164, and is secured to the bottom of the base 14. The coilspring 166 is positioned and maintained in an expanded state between aninterior surface of the central portion 165 and the bottom surface ofthe base 14.

Referring to FIG. 5, during the filter cleaning maintenance operation,the sprayed water and dislodged debris flow downward to the bottom ofthe base 14 (or tray 150 if present), such that the force of the waterwill push the central portion 165 and cover 163 downward so that thecoil spring 164 compresses, and the cover 163 is displaced from andbelow the outlet port 160. The sprayed water and small amounts of debriscan then flow through the outlet port 160 and out of the interiorchamber 26 so that the interior chamber does not fill up with thecleansing water. Once the water from the external source is turned off,the compressed coiled spring 164 returns to its normal expanded stateand the cover 163 rises upward to be seated against the periphery of theoutlet port 160 formed in the base 14 or the tray 150.

A person of ordinary skill in the art will appreciate that removal ofthe debris from the interior chamber 26 is not limited to the tray 150and outlet port 160 embodiments as described above, as other embodimentsfor removing debris from the interior chamber 26 are envisioned. Forexample, debris that is washed down to the bottom of the interiorchamber can also be removed by providing access through one or more sidewalls of the housing (e.g., an access panel), or by lifting the housingcover up and away from the base, among other techniques.

Referring to FIG. 9, an access panel 15 (shown in phantom) is providedalong a sidewall of the housing 11. The access panel 15 isillustratively shown as being hinged 17 or otherwise fastened to thebase 14. A person of ordinary skill in the art will appreciate one ormore access panels can be hinged or otherwise secured to other portionsof the cleaner housing, such as an adjacent sidewall of the housing 11.The access panel 15 is opened manually to permit an operator to removethe debris from the interior chamber 26. A person of ordinary skill inthe art will further appreciate that any access panel 15 and/or otherdebris outlet port(s) is sealed during the pool cleaning operations ofthe cleaner 10 to prevent any water from entering therethrough. In thismanner, the low pressure environment in the interior chamber 26, whichis created by the water pump, is maximized to draw the pool water onlythrough the inlet ports 16 provided in the base 14 or tray 150 of thecleaner 10.

The self-propelled robotic pool or tank cleaner includes an internalfilter backwash assembly 80 that sprays or otherwise delivers apressurized stream of water over an internal filter body 52 within theinterior chamber 26 of the cleaner 10. The positioning of the backwashassembly 80 within the interior chamber 26 of the housing 11 permitswater sprayed onto the filter body 52 to naturally flow downwards due togravitational forces to help dislodge and remove debris from the filtermedium of the filter body 52. The cleansing water and debris can then beremoved from the interior chamber 26 of the cleaner 10 by removing thehousing cover from the base 14 or slidably removing a tray 150 to openthe bottom portion of the base and allow the debris to fall out andprovide additional access into the interior chamber 26 and filter body52 for additional cleaning by the user.

The backwash assembly of the present invention has numerous advantagesnot before known to the prior art. One advantage is that a user canquickly and easily attach a garden hose to the housing cover and providea steady supply of water to an interior sprinkler assembly, whichexpediently and efficiently cleans the interior chamber and filterdevices therein. Another advantage is that the water is more evenlysprayed or otherwise dispersed over the filter body to efficientlydislodge debris from the fabric medium (e.g., mesh) of the filter.Additionally, the even distribution of water over the filter bodyminimizes the possibility of damage to the filter medium from aconcentrated stream of water being directed at a particular area of thefilter fabric. Moreover, the backwash assembly's cleaning efficiencieswhich are achieved by evenly dispersing the water to clean the interiorchamber helps to reduce water consumption during the cleaning process.

A further advantage includes the rinsing of the filter without having tomanually remove it from the interior chamber of the cleaner. In thismanner, damage to the filter is minimized because the user does not haveto physically remove the filter from the cleaner, handle it during therinsing process, and then properly reinstall the filter in the cleaner.

While the foregoing is directed to embodiments of the present inventionthat have been illustrated in the accompanying drawings, other andfurther embodiments and advantages of the invention can be devised bythose of ordinary skill in the art based on this description withoutdeparting from the basic scope of the invention, which is to bedetermined by the claims that follow.

I claim:
 1. A method for cleaning a filter mounted in an interiorchamber of a self-propelled robotic cleaning apparatus that cleans asubmerged surface of a pool, the method comprising: coupling an externalsource of pressurized fluid to a fluid-tight adapter provided on ahousing of the cleaning apparatus, the adapter in fluid communicationwith an internal backwash assembly mounted within the interior chamber;providing a flow of the pressurized fluid from the external fluid sourceto the internal backwash assembly mounted within the interior chamberfor a predetermined time; distributing the fluid from the internalbackwash assembly towards at least a portion of the filter which ismounted in the interior chamber to dislodge debris from the filter; anddischarging the fluid and dislodged debris from the interior chamberthrough a debris discharge opening formed in the housing, the debrisdischarge opening having a releasable closure.
 2. The method of claim 1,wherein the discharging step comprises discharging the fluid anddislodged debris from the filter through the debris discharge opening.3. The method of claim 1, wherein said distributing step comprisesproviding the flow of the pressurized fluid within the chamber throughat least one perforated tube of the internal backwash assembly whichextends around at least a portion of the filter.
 4. The method of claim1, wherein said distributing step comprises providing the flow of thepressurized fluid within the chamber through a sprinkler arm of theinternal backwash assembly that oscillates back and forth at apredetermined rate proximate said filter.
 5. The method of claim 1,wherein said distributing step comprises providing the flow of thepressurized fluid within the chamber through one or more sprinkler armsof the internal backwash assembly that rotate and are positionedproximate said filter.
 6. The method of claim 1, wherein saiddischarging step comprises releasing the fluid and debris from withinthe interior chamber of the cleaning apparatus through a tray mounted tothe housing beneath the filter.
 7. The method of claim 1, wherein saiddischarging step comprises releasing the fluid and debris from withinthe interior chamber of the housing through an access panel.
 8. Themethod of claim 1, wherein said coupling step comprises connecting theexternal source of fluid to a shutoff valve located proximate thecleaning housing.
 9. The method of claim 1, wherein prior to saidcoupling step the method comprises terminating a cleaning operation ofthe cleaning apparatus and removing the cleaning apparatus from the poolto a location remote from the pool.
 10. A method for cleaning a filtermounted in an interior chamber of a self-propelled robotic cleaningapparatus that cleans a submerged surface of a pool, the methodcomprising: providing the robotic cleaning apparatus with an internalbackwashing assembly mounted within the interior chamber and aconnection to receive a pressurized fluid from an external fluid source,distributing the pressurized fluid from the internal backwashingassembly towards at least a portion of the filter; and discharging thefluid and debris from the interior chamber through a debris dischargeopening formed in a housing of the cleaning apparatus, the debrisdischarge opening having a releasable closure.
 11. The method of claim10, wherein the discharging step comprises releasing the pressurizedfluid and debris from the filter through the debris discharge opening.12. The method of claim 10, wherein said distributing step comprisesproviding the flow of the pressurized fluid within the chamber throughat least one perforated tube of the internal backwash assembly whichextends around at least a portion of the filter.
 13. The method of claim10, wherein said distributing step comprises providing the flow of thepressurized fluid within the chamber through a sprinkler arm of theinternal backwash assembly that oscillates back and forth at apredetermined rate proximate said filter.
 14. The method of claim 10,wherein said distributing step comprises providing the flow of thepressurized fluid within the chamber through one or more sprinkler armsof the internal backwash assembly that rotate and are positionedproximate said filter.
 15. The method of claim 10, wherein saiddischarging step comprises discharging the fluid and debris from withinthe interior chamber of the cleaning apparatus through a tray mounted tothe housing beneath the filter.
 16. The method of claim 10, wherein saiddischarging step comprises discharging the fluid and debris from withinthe interior chamber of the housing through an access panel.
 17. Themethod of claim 10, wherein said proving step comprises connecting theexternal source of pressurized fluid to the internal backwashingassembly via a shutoff valve which is attached to the cleaningapparatus.